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Turkish Journal of Agriculture and Forestry

Author ORCID Identifier

HACER ERDEM KIZILTUNÇ: 0000-0002-6636-956X

HALİS ŞAKİROĞLU: 0000-0002-2964-4497

MİNE AKSOY: 0000-0002-2430-8769

DOI

10.55730/1300-011X.3228

Abstract

Herbicide selectivity is determined by the variability of herbicide degradation processes in weeds and crops. GlutathioneS-transferases (GSTs) have been widely studied in plants because of their role in herbicide metabolism. GSTs metabolize herbicides bycatalyzing reduced glutathione (GSH) conjugation. The significance of GSTs in herbicide metabolism has been understood by examiningGST in some plants. In this study, a GST enzyme was purified from broccoli using an affinity chromatography (glutathione agarose)method to contribute to the elucidation of plant GSTs. A characterization of the purified broccoli GST enzyme was then carried out.In the last step, the inhibition profiles of some selected types of herbicides on the activity of the broccoli GST enzyme were studied. Inthe purification studies conducted as part of the study, the GST enzyme was purified 101.34-fold with a yield of 18.84% from broccoli.The optimal conditions (temperature, pH, ionic strength) of broccoli GST were found to be 60 °C, 7.5, and 1.25 M, respectively. TheKM constants of broccoli GST were determined to be 0.465 and 2.355 mM for its two substrates, 1-chloro-2,4-dinitrobenzene and GSH,respectively, and the Vmax for the same two substrates was determined to be 0.251 and 0.424 EU/mL, respectively. SDS-PAGE was usedto check the purity of the enzyme, and it was determined to have a molecular weight in the range of 35–40 kDa. Inhibition studies werealso conducted to determine the inhibitory effects of the herbicides pendimethalin, bentazone, and glyphosate. The IC50 values weredetermined to be 173.25, 0.438, and 0.536 μM for pendimethalin, bentazone, and glyphosate, respectively. The best inhibitor of the GSTenzyme was found to be bentazone, with the lowest Ki value of 0.318 ± 0.079 μM.

Keywords

Broccoli, glutathione S-transferase, purification, herbicide, inhibition

First Page

888

Last Page

897

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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